Fabrication And Application Research Of White Light LED Structured Coating Based On Electric Field Induction

Light Emitting Diode(LED)has gradually become the mainstream lighting source at this stage due to its advantages of energy conservation,high efficiency and long life.With the popularity of applications and the improvement of lighting quality requirements,how to improve the optical quality of LED devices is an urgent problem to be solved.The optimization of the optical quality depends on the application of new fluorescent materials such as quantum dots,and on the other hand depends on optimizing the white light LED packaging process and the fluorescent coating structure.Electric field induction,as a simple and efficient structural forming method,has a good adaptability and white light LED packaging process.The electric field-assisted packaging process can effectively control the contour of the fluorescent coating and achieve better optical management inside the white LED device.In this paper,the white LED packaging process based on electric field induction method is designed both on the macro scale and micro scale,and the correlated process parameters are studied.The fluorescent coating optimization is carried out for the problems of low light extraction efficiency and angular color uniformity,and improve the optical quality of white LED device in this way.In theoretical aspect,the mechanism of the action between electric field and fluid are discussed.The theoretical model of process is established based on electrohydrodynamics theory.Based on theoretical analysis,the process simulation model is established by using the COMSOL Multiphysics finite element analysis software to analyze the force on the fluid in the electric field,the influence of the process parameters on the liquid rheological behavior,and the control of the formed structure.This part of work provides theoretical guidance for process design and process experiments.In the uniform spatial distribution of electric field intensity situation,the test of forming micro-disordered structure by electric field induction method is explored.The effects of process parameters such as voltage,electrode spacing and polymer film thickness on the twodimensional distribution of micro-structures were investigated in a plate electrode model.Furthermore,a disordered microlens structure fabricating method and a hierarchical structure fabricating method with roughening electrode are developed for the purpose of improving the scattering performance of the structure.As a meanwhile,the types and complexity of the surface morphology of the structure are expanded in the method development.In the uniform spatial distribution of electric field intensity situation,the forming law of the micro-structure array fabricated by electric field induction method is explored.The plate electrode is replaced by a patterned electrode with micro/nano structure on its surface to form the structure array which is matching the electrode pattern.The influences of process parameters such as the voltage,electrode spacing and polymer film thickness on the three-dimensional contour of the array structure unit are investigated.In addition,the electric field-assisted microlens array forming method is designed,and the surface curvature of the microlens structure is adjusted by the electric field parameter to realize the controllability of the structure aspect ratio.Based on the research of electric field induction fabrication process,the performance optimization of white LED devices was carried out.The morphology of the quantum dot device coating was adjusted on macro scale,and on the microscopic,the disordered microstructure and ordered microstructure were introduced into the remote quantum dot coating to achieve optical optimization.The concave microlens array structure is coupled in the intelligent correlative color temperature tunable LED to improve the spatial distribution uniformity of lights color.Perform performance characterization of the above optimized device to verify its optimization effect.